How to get model properties in a sensor plugin?

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I am developing a underwater sonar for gazebo. It uses "some" rays booth vertically and horizontally in order to find obstacles and it also rotates over itself. I am already capable of getting the info from all the rays and publishing it to ROS in a pointcloud2 message, but I also need the heading at the "same" timestamp of the rays reading. Which can be accessed in a model plugin but not from the sensor plugin which publish the sensor output.. What would be the best way to access this info from the sensor plugin?